Adequate interval for the monitoring of vital signs during endotracheal intubation.

BACKGROUND: In the perioperative period, it may be inappropriate to monitor vital signs during endotracheal intubation using the same interval as during a hemodynamically stable period. The aim of the present study was to determine whether it is appropriate to use the same intervals used during the endotracheal intubation and stable periods to monitor vital signs of patients under general anesthesia. METHODS: The mean arterial pressure (MAP) and heart rate (HR) were continuously measured during endotracheal intubation (15 min after intubation) and hemodynamically stable (15 min before skin incision) periods in 24 general anesthesia patients. Data was considered "unrecognized" when continuously measured values were 30% more or less than the monitored value measured at 5- or 2.5-min intervals. The incidence of unrecognized data during endotracheal intubation was compared to that during the hemodynamically stable period. RESULT: There were significantly more unrecognized MAP data measured at 5-min intervals during endotracheal intubation than during the hemodynamically stable period (p value <0.05). However, there was no difference in the incidence of unrecognized MAP data at 2.5 min intervals or HR data at 5 or 2.5 min intervals between during the endotracheal intubation and hemodynamically stable periods. CONCLUSION: A 5-min interval throughout the operation period was not appropriate for monitoring vital signs. Therefore, , a 2.5-min interval is recommended for monitoring the MAP during endotracheal intubation.

The effect of lung deflation on the position of the pleura during subclavian vein cannulation in infants receiving mechanical ventilation: an ultrasound study.

We evaluated the effect of lung deflation on the relative position of the pleura compared with a reference line during supra- and infraclavicular approaches to the right subclavian vein. The reference line was drawn relative to the predicted pathway of the needle. The distances between the pleura and the reference line for supra- and infraclavicular approaches were measured during inspiration and expiration in 41 infants. Measurements were repeated with the application of 5 cmH2O positive end-expiratory pressure (PEEP) and in the Trendelenburg position. Lung deflation during the supraclavicular approach significantly decreased the volume of lung crossing the reference line by a median (IQR [range]) of 1.0 (0.6 to 1.3 [0.0 to 4.8]) mm, p < 0.001, irrespective of the application of PEEP or patient position. However, during the infraclavicular approach, lung deflation showed no change in the distance of the pleura from the reference line regardless of PEEP or patient position. We conclude that lung deflation moves the lung apex caudally and can reduce the potential risk of pneumothorax during a supraclavicular approach to the right subclavian vein in infants.

Predicting the optimal depth of left-sided central venous catheters in children.

The aim of this study was to predict the optimal depth for insertion of a left-sided central venous catheter in children. Using 3D chest computed tomography angiography, we measured the distance from a point where the internal jugular vein is at the superior border of the clavicle, and from a point where the subclavian vein is inferior to the anterior border of the clavicle, to the junction of the superior vena cava and the right atrium in 257 children. Linear regression analysis revealed that the distances correlated with age, weight and height. Simple formulae for the depth of a central venous catheter via the left internal jugular vein (0.07 × height (cm)) and the left subclavian vein (0.08 × height (cm)) were developed to predict placement of the central venous catheter tip at the junction of the superior vena cava with the right atrium. Using these fomulae, the proportion of catheter tips predicted to be correctly located was 98.5% (95% CI 96.8-100%) and 94.0% (95% CI 90.8-97.3%), respectively.

Comparison between ultrasound-guided supraclavicular and infraclavicular approaches for subclavian venous catheterization in children--a randomized trial.

BACKGROUND: Ultrasound (US)-guided subclavian vein (SCV) catheterization via the supraclavicular (SC) or infraclavicular (IC) approaches can be useful in children. The purpose of this study was to compare the efficacy of these approaches. METHODS: This prospective, randomized study included 98 children who were <3 years old, and who were divided into two groups: the SC group (n=49) and the IC group (n=49). All SCV catheterizations were guided by US and performed by a single experienced anaesthesiologist. Data regarding puncture time, number of attempts, successful guidewire insertion, catheter insertion time, and complications were analysed. RESULTS: The median puncture time was longer in the IC group than the SC group (48 vs 36 s, P=0.02). Multiple attempts (number of attempts >3) were more frequently required in the IC group than the SC group (24.5 vs 6.1%, P=0.01). The incidence of guidewire misplacement was higher in the IC group than that of the SC group [10 (20.4%) vs 0 (0%), P=0.001]. Catheterization was successfully performed in all patients. No pneumothoraces or arterial punctures occurred in either group. CONCLUSION: During SCV catheterization under US guidance in paediatric patients, the SC approach yielded a shorter puncture time and decreased the incidence of guidewire misplacement when compared with the IC approach.

Prediction of fluid responsiveness in mechanically ventilated children undergoing neurosurgery.

BACKGROUND: The purpose of this study was to evaluate the clinical usefulness of static and dynamic variables for the prediction of fluid responsiveness in children under general anaesthesia. METHODS: Thirty-three mechanically ventilated children received 10 ml kg(-1) colloid for 10 min while stable during surgery. Arterial pressure, heart rate, central venous pressure (CVP), and pleth variability index (PVI), in addition to variation in systolic pressure, pulse pressure (including Δdown and Δup), respiratory aortic blood flow velocity (ΔVpeak), and inferior vena cava diameter were measured before and after volume expansion. Patients were classified as responders to fluid loading if their stroke volume index (SVI) increased by at least 10%. RESULTS: There were 15 volume responders and 18 non-responders. Of the variables examined, ΔVpeak (r=0.516, P=0.004) and PVI (r=0.49, P=0.004) before volume expansion were significantly correlated with changes in SVI. The receiver-operating characteristic (ROC) curve analysis showed that PVI and ΔVpeak predicted fluid responsiveness. Areas under the ROC curves of PVI and ΔVpeak were statistically larger than that of CVP (P=0.006 and 0.014, respectively). However, those of other variables were similar to that of CVP. CONCLUSIONS: ΔVpeak and PVI can be used to predict fluid responsiveness in mechanically ventilated children under general anaesthesia. The other static and dynamic variables assessed in this study were not found to predict fluid responsiveness significantly in children. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01364103.

A randomised trial comparing the i-gel (TM) with the LMA Classic (TM) in children.

We performed a prospective, randomised trial comparing the i-gel(TM) with the LMA Classic(TM) in children undergoing general anaesthesia. Ninety-nine healthy patients were randomly assigned to either the i-gel or the LMA Classic. The outcomes measured were airway leak pressure, ease of insertion, time taken for insertion, fibreoptic examination and complications. Median (IQR [range]) time to successful device placement was shorter with the i-gel (17.0 (13.8-20.0 [10.0-20.0]) s) compared with the LMA Classic (21.0 (17.5-25.0 [15.0-70.0]) s, p = 0.002). There was no significant difference in oropharyngeal leak pressure between the two devices. A good fibreoptic view of the glottis was obtained in 74% of the i-gel group and in 43% of the LMA Classic group (p < 0.001). There were no significant complications. In conclusion, the i-gel provided a similar leak pressure, but a shorter insertion time and improved glottic view compared with the LMA Classic in children.

Effect of remote ischaemic preconditioning on ischaemic-reperfusion injury in pulmonary hypertensive infants receiving ventricular septal defect repair.

BACKGROUND: Remote ischaemic preconditioning (RIPC) can reduce ischaemic-reperfusion injury in distant organs. The myocardial and pulmonary protective effect of RIPC in infants with pulmonary hypertension remains unclear. We conducted a randomized controlled trial to evaluate the effect of RIPC in infants receiving ventricular septal defect (VSD) repair. METHODS: We studied 55 infants with pulmonary hypertension undergoing VSD repair (RIPC group, n=27; control group, n=28). RIPC consisted of four 5 min cycles of lower limb ischaemia and reperfusion. Serum troponin I (TnI) concentrations were measured after induction of anaesthesia and at 1, 6, 12, and 24 h after surgery. Other clinical data such as inotropic score, lung compliance, alveolar-arterial oxygen gradient, oxygen index, mechanical ventilation time, and length of intensive care unit stay were also recorded at each interval. RESULTS: No differences in patient or surgical characteristics were observed between the two groups. There were no significant differences in postoperative TnI levels according to time (P=0.35) or the total amount of TnI release, expressed as the area under the curve over the 24 h after surgery [RIPC vs control: 207.6 (134.0) vs 274.6 (263.7) h ng ml(-1), P=0.24]. All other clinical data were also comparable. CONCLUSIONS: RIPC does not reduce the postoperative TnI release after VSD repair in infants with pulmonary hypertension. Additionally, it is difficult to find significant clinical benefits of RIPC in this population. The effect of RIPC varies according to clinical situation and patient condition. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01313832.

Usefulness of ultrasound for selecting a correctly sized uncuffed tracheal tube for paediatric patients.

The purpose of this study was to assess whether ultrasonography is useful for determining uncuffed tracheal tube sizes for paediatric patients. The equation for selecting the correctly sized tracheal tube was developed using data on the subglottic diameter measured by ultrasonography and air leak test. The efficacy of the new equation was evaluated by comparing it with the conventional age-based formula (4 + age/4) in another 100 patients. Tracheal tube sizes were selected using two methods, and air leakage pressure was measured after each intubation. The ultrasonographic method allowed the correct tube size to be selected in 60% of cases, whereas the age-based method enabled this in 31% of cases (p < 0.001). Ultrasound can offer a useful means of selecting correct tracheal tube size compared with the age-based formula in paediatric patients. However, even using ultrasound, the success rate of correct tube size selection is still not very high.

Potential risk for intra-aortic balloon-induced obstruction to the celiac axis or the renal artery in the Asian population.

To evaluate the potential risk for intra-aortic balloon (IAB)-induced obstruction to the celiac axis (CA) or the renal artery (RA) when IAB size is chosen according to patient height and the tip is placed 2 cm distal to the origin of the left subclavian artery (LSCA), the computed tomography images of 150 Asian adults were reviewed to identify the distance from the LSCA to the CA (LSCA-CA) and to the RA (LSCA-RA). The diameter of the aorta at the level of the T9 vertebra, CA, and RA was also measured. The length and caliber of the IAB was selected according to two manufacturer's recommendations (Datascope Corp and Tokai Medical Products). The Datascope IAB potentially blocked the CA in 84 % and the RA in 66 %, while the Tokai IAB obstructed the CA in 61 % and the RA in 10 % of cases. The caliber of the IAB overlying the orifice of the RA was longer than the diameter of the aorta in 5 cases (3.3 %) using the Datascope IAB, and in 1 case (0.7 %) using the Tokai IAB. When placing an IAB selected based on patient height, the IAB could obstruct the orifice of the CA and RA in the majority of Asian patients, especially a Datascope IAB.